Further studies of [omega-(haloalkylstannyl)alkyl]phosphine oxides. Structures of bis[2-(bromodimethylstannyl)ethyl]phenylphosphine oxide and t-butyl[3-(iododimethylstannyl)propyl]phenylphosphine oxide

The crystal structures of bis[2-(bromodimethylstannyl)ethyl]phenylphosphine oxide 3 (X = Br), and t-butyl[3-(iododimethylstannyl)propyl]phenylphosphine oxide 7 (X = 1), have been determined. Compound 7 (X = 1), grown from EtOH solution, is a chelated complex as a consequence of an intramolecular Sn-O interaction and hence contrasts with the previously reported [3(iododimethylstannyl)propyl]diphenylphosphine oxide, grown from alcohol media solution, which has an intermolecular Sn-O linked chain structure. Molecules of 7 (X = 1) are linked into double chains via C-H-I and C-H-pi interactions. Compound 3 (X = Br), isostructural with previously reported 3 (X = Cl) obtained from CH2Cl2 solution, contains two distinct trigonal bipyramidal tin centres. One Sn centre is intramolecularly bound to the O, i.e., one PhP(O)CH2CH2 fragment is acting as a C,O-chelating unit, while the other Sn centre is weakly bonded to a Br ligand from another molecule to set up zig zag chains of molecules. Intermolecular interactions, C-H-Br and C-H-pi, create a double layer of molecules. Detailed H-1 NMR spectra of 3 are reported. (C) 2003 Elsevier Ltd. All rights reserved.